Readers’ insatiable appetite for the darkest of domestic dramas has sent Paula Hawkins’s very English thriller about a woman who drinks too much, catches a train and sees something she shouldn’t soaring to the top of bestseller charts on both sides of the Atlantic, selling almost two million copies in less than three months.

The Girl on the Train has sold more than 122,000 hardbacks in the UK since 15 January, with digital sales and editions published in the rest of the world taking the total to “approaching two million”, according to UK publisher Doubleday – and the numbers are continuing to mushroom.

Hawkins is currently the UK’s fastest-selling book, hitting the top of the chart for the first time last week after selling 16,157 copies in the UK, according to book sales monitor Nielsen BookScan – more than the combined sales of the next eight fiction hardbacks on the list, according to the Bookseller. It is already one of the 20 bestselling fiction hardbacks published since 2012, said the magazine, in 16th slot ahead of Donna Tartt’s Pulitzer-winning The Goldfinch, and is tipped to outsell JK Rowling’s thriller The Cuckoo’s Calling “over the next few days”.

In the US, meanwhile, sales in hardback are already over 380,000, with ebooks boosting the total to “well over a million copies”, said Jynne Martin at Riverhead. “The book has been No 1 on the New York Times bestseller list for 11 weeks now,” she added. “It has one of the fastest rates of sale of any hardcover we’ve ever seen.”

“We’ve all been completely thrown and blown away by its success,” said Alison Barrow at Doubleday.

The novel opens as Rachel, a commuter on the train from Euston to Ashbury, pours herself an after-work gin and tonic. The reader is drawn into her obsession with a couple who live in one of the houses she can see from the train, an obsession which builds until she begins to embroil herself in their lives. Then, one morning, she wakes up, horribly hungover, with a sense of impending doom.

“I don’t know, I don’t remember,” Hawkins writes. “I went to the pub, I got on to the train, I was at the station, I was on the street. Blenheim Road. I went to Blenheim Road. It comes over me like a wave, black dread. Something happened, I know it did. I can’t picture it, but I can feel it. The inside of my mouth hurts, as though I’ve bitten my cheek, there’s a metallic tang of blood on my tongue. I feel nauseated, dizzy.”

Described as the new Gone Girl before its release, The Girl on the Train is more than matching Gillian Flynn’s smash-hit tale of an imploding marriage in UK sales, with the first 12 weeks since publication notching up £1.06m in hardback sales as compared to Gone Girl’s initial paperback sales of £924,000.

“Even The Da Vinci Code was not so massive in hardback,” said Barrow, “it was in paperback that it really took off, and with The Da Vinci Code it absolutely started in the US … This is a hardback from a pretty unknown writer [and] it feels quite exceptional.”

“The novel received rave reviews from every major US outlet right at publication and the word of mouth has been spectacular. And the universal reaction, from everyday readers to celebrities (as disparate as Reese Witherspoon and Stephen King), is that it’s one of the most suspenseful books they’ve ever read, with an ending you’ll never see coming. I think hearing so many different types of readers, critics and booksellers all have that same response has been a big part of igniting the wildfire here,” said Martin in the US, adding that despite Hawkins’s very English focus, the novel “feels universal in its themes: the curiosity and voyeurism, wondering what other people’s lives are like; the envy, longing and imagination run wild about what other people’s homes, families, love lives and relationships might be like.

“And while we have plenty of commuter trains throughout the US, you don’t have to be a regular train rider to understand the impulse to peek into another person’s life, or to be hooked by the idea of what you might do if you witnessed something terrible while snooping,” she said.

Hawkins was born and brought up in Zimbabwe. She moved to London in 1989, and worked as a journalist for 15 years before she turned to fiction, publishing under the Amy Silver pseudonym before penning her first psychological thriller as Paula Hawkins.

Barrow said the psychological crime genre was “absolutely buzzing”. “There’s a real appetite for these books,” she said, pointing to the previous success of SJ Watson’s tale of a woman with memory loss trying to make sense of her life with a husband she can’t remember, Before I Go to Sleep, and to Flynn’s Gone Girl, which has given rise to a host of similarly-titled books, from Kate Hamer’s The Girl in the Red Coat, in which a girl is abducted from her mother, to Peter Swanson’s The Girl with a Clock for a Heart, which sees an inept hero struggle to protect his enigmatic ex.